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package solver.variables.view;
import gnu.trove.map.hash.THashMap;
import solver.ICause;
import solver.Solver;
import solver.exception.ContradictionException;
import solver.explanations.Explanation;
import solver.explanations.VariableState;
import solver.variables.IntVar;
import solver.variables.VariableFactory;
import solver.variables.delta.IIntDeltaMonitor;
import solver.variables.delta.NoDelta;
import solver.variables.events.IntEventType;
import util.iterators.DisposableRangeIterator;
import util.iterators.DisposableValueIterator;
import util.tools.MathUtils;
/**
* declare an IntVar based on X and C, such as X * C
* <p/>
* Based on "Views and Iterators for Generic Constraint Implementations" <br/>
* C. Shulte and G. Tack.<br/>
* Eleventh International Conference on Principles and Practice of Constraint Programming
*
* @author Charles Prud'homme
* @since 04/02/11
*/
public final class ScaleView extends IntView {
public final int cste;
public ScaleView(final IntVar var, final int cste, Solver solver) {
super("(" + var.getName() + "*" + cste + ")", var, solver);
assert (cste > 0) : "view cste must be >0";
this.cste = cste;
}
@Override
public IIntDeltaMonitor monitorDelta(ICause propagator) {
var.createDelta();
if (var.getDelta() == NoDelta.singleton) {
return IIntDeltaMonitor.Default.NONE;
// throw new UnsupportedOperationException();
}
return new ViewDeltaMonitor(var.monitorDelta(propagator), propagator) {
@Override
protected int transform(int value) {
return cste * value;
}
};
}
@Override
public boolean removeValue(int value, ICause cause) throws ContradictionException {
assert cause != null;
if (value % cste == 0) {
int inf = getLB();
int sup = getUB();
if (inf <= value && value <= sup) {
IntEventType e = IntEventType.REMOVE;
boolean done = var.removeValue(value / cste, this);
if (done) {
if (value == inf) {
e = IntEventType.INCLOW;
} else if (value == sup) {
e = IntEventType.DECUPP;
}
if (this.isInstantiated()) {
e = IntEventType.INSTANTIATE;
}
this.notifyPropagators(e, cause);
return true;
}
}
}
return false;
}
@Override
public boolean removeInterval(int from, int to, ICause cause) throws ContradictionException {
assert cause != null;
if (from <= getLB()) {
return updateLowerBound(to + 1, cause);
} else if (getUB() <= to) {
return updateUpperBound(from - 1, cause);
} else {
boolean done = var.removeInterval(MathUtils.divCeil(from, cste), MathUtils.divFloor(to, cste), this);
if (done) {
notifyPropagators(IntEventType.REMOVE, cause);
}
return done;
}
}
@Override
public boolean instantiateTo(int value, ICause cause) throws ContradictionException {
assert cause != null;
if (value % cste != 0) {
contradiction(cause, IntEventType.INSTANTIATE, "Not a multiple of " + cste);
}
boolean done = var.instantiateTo(value / cste, this);
if (done) {
notifyPropagators(IntEventType.INSTANTIATE, cause);
return true;
}
return false;
}
@Override
public boolean updateLowerBound(int value, ICause cause) throws ContradictionException {
assert cause != null;
int old = this.getLB();
if (old < value) {
IntEventType e = IntEventType.INCLOW;
boolean done = var.updateLowerBound(MathUtils.divCeil(value, cste), this);
if (isInstantiated()) {
e = IntEventType.INSTANTIATE;
}
if (done) {
this.notifyPropagators(e, cause);
return true;
}
}
return false;
}
@Override
public boolean updateUpperBound(int value, ICause cause) throws ContradictionException {
assert cause != null;
int old = this.getUB();
if (old > value) {
IntEventType e = IntEventType.DECUPP;
boolean done = var.updateUpperBound(MathUtils.divFloor(value, cste), this);
if (isInstantiated()) {
e = IntEventType.INSTANTIATE;
}
if (done) {
this.notifyPropagators(e, cause);
return true;
}
}
return false;
}
@Override
public boolean contains(int value) {
return value % cste == 0 && var.contains(value / cste);
}
@Override
public boolean isInstantiatedTo(int value) {
return value % cste == 0 && var.isInstantiatedTo(value / cste);
}
@Override
public boolean instantiatedTo(int value) {
return isInstantiatedTo(value);
}
@Override
public int getValue() {
return var.getValue() * cste;
}
@Override
public int getLB() {
return var.getLB() * cste;
}
@Override
public int getUB() {
return var.getUB() * cste;
}
@Override
public int nextValue(int v) {
int value = var.nextValue(MathUtils.divFloor(v, cste));
if (value == Integer.MAX_VALUE) {
return value;
}
return value * cste;
}
@Override
public int previousValue(int v) {
int value = var.previousValue(MathUtils.divCeil(v, cste));
if (value == Integer.MIN_VALUE) {
return Integer.MIN_VALUE;
}
return value * cste;
}
@Override
public String toString() {
return "(" + this.var.toString() + " * " + this.cste + ") = [" + getLB() + "," + getUB() + "]";
}
@Override
public IntVar duplicate() {
return VariableFactory.scale(this.var, this.cste);
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
this.var.duplicate(solver, identitymap);
ScaleView clone = new ScaleView((IntVar) identitymap.get(this.var), this.cste, solver);
identitymap.put(this, clone);
}
}
@Override
public void explain(VariableState what, int val, Explanation to) {
var.explain(what, val / cste, to);
}
@Override
public void explain(VariableState what, Explanation to) {
if (cste > 0) {
var.explain(what, to);
} else {
switch (what) {
case UB:
var.explain(VariableState.LB, to);
break;
case LB:
var.explain(VariableState.UB, to);
break;
default:
var.explain(what, to);
break;
}
}
}
@Override
public DisposableValueIterator getValueIterator(boolean bottomUp) {
if (_viterator == null || !_viterator.isReusable()) {
_viterator = new DisposableValueIterator() {
DisposableValueIterator vit;
@Override
public void bottomUpInit() {
super.bottomUpInit();
vit = var.getValueIterator(true);
}
@Override
public void topDownInit() {
super.topDownInit();
vit = var.getValueIterator(false);
}
@Override
public boolean hasNext() {
return vit.hasNext();
}
@Override
public boolean hasPrevious() {
return vit.hasPrevious();
}
@Override
public int next() {
return vit.next() * cste;
}
@Override
public int previous() {
return vit.previous() * cste;
}
@Override
public void dispose() {
super.dispose();
vit.dispose();
}
};
}
if (bottomUp) {
_viterator.bottomUpInit();
} else {
_viterator.topDownInit();
}
return _viterator;
}
@Override
public DisposableRangeIterator getRangeIterator(boolean bottomUp) {
if (cste == 1) return var.getRangeIterator(bottomUp);
// cste > 2, so no range anymore!
if (_riterator == null || !_riterator.isReusable()) {
_riterator = new DisposableRangeIterator() {
DisposableValueIterator vit;
int min
,
max;
@Override
public void bottomUpInit() {
vit = getValueIterator(true);
if (vit.hasNext()) {
min = vit.next();
}
max = min;
}
@Override
public void topDownInit() {
vit = getValueIterator(false);
if (vit.hasPrevious()) {
max = vit.previous();
}
min = max;
}
@Override
public boolean hasNext() {
return min != Integer.MAX_VALUE;
}
@Override
public boolean hasPrevious() {
return max != -Integer.MAX_VALUE;
}
@Override
public void next() {
if (vit.hasNext()) {
min = max = vit.next();
} else {
min = Integer.MAX_VALUE;
}
}
@Override
public void previous() {
if (vit.hasPrevious()) {
max = vit.previous();
min = max;
} else {
max = -Integer.MAX_VALUE;
}
}
@Override
public int min() {
return min;
}
@Override
public int max() {
return max;
}
};
}
if (bottomUp) {
_riterator.bottomUpInit();
} else {
_riterator.topDownInit();
}
return _riterator;
}
}